scholarly journals Effect of NS-DBD Actuator Parameters on the Aerodynamic Performance of a Flap Lifting Device

2019 ◽  
Vol 9 (23) ◽  
pp. 5213 ◽  
Author(s):  
Kun Chen ◽  
Chen-Yao Wei ◽  
Zhi-Wei Shi
Keyword(s):  
Energy Density ◽  
Flow Field ◽  
Drag Reduction ◽  
Pulse Width ◽  
High Efficiency ◽  
Aerodynamic Drag ◽  
Pulse Discharge ◽  
Excitation Frequency ◽  
Aerodynamic Performance ◽  
Discharge Pulse

The flap lift device is an important part of the conventional configuration of aircrafts and has an important impact on the aerodynamic performance. In this paper, a high-efficiency, simple, and energy-saving nanosecond dielectric barrier discharge (DBD) plasma actuator is placed in the vicinity of the flap lift device to improve the aerodynamic performance of the flap by controlling the flow field. The two-dimensional airfoil GAW-1 and its 29% flap were selected as the research objects, and the nanosecond (NS) DBD actuators were fixed at different locations near the deflection angle of the 10°flap. The excitation frequency, pulse width, and energy density parameters of the pulse discharge were adjusted, and then, the effects of parameter changes on aerodynamic characteristics of the airfoil were studied by numerical simulation. The simulation results show that adjusting the excitation frequency on the aerodynamic drag is weak and that the effect on the aerodynamic lift is obvious. The increase of the discharge pulse width will have a more significant effect on the flow field, i.e., a proper increase of the discharge pulse width can achieve better drag reduction, and increase lift after a stall at a high angle of attack. Although the increase of discharge energy density can strengthen the pulse perturbation effect on the flow field, it also contributes to some adverse effects and has no obvious optimization effect on the control efficiency of lift increase and drag reduction.

Aerodynamic Drag Reduction of SUV Based on Underbody Cover Board

2014 ◽  
Vol 602-605 ◽  
pp. 477-480
Author(s):  
Jing Yu Wang ◽  
Bao Yu Wang ◽  
Xing Jun Hu ◽  
Lei Liao
Keyword(s):  
Flow Field ◽  
Drag Reduction ◽  
Drag Coefficient ◽  
Aerodynamic Drag ◽  
Flow Line ◽  
Wind Tunnel Test ◽  
Aerodynamic Performance ◽  
Simulation Based ◽  
Aerodynamic Drag Coefficient ◽  
Aerodynamic Drag Reduction

The principles and method of computational fluid dynamics were applied to numerical simulate the external flow field about the SUV model. The hybrid mesh of tetrahedral and triangular prismatic as well as the turbulence model of Realizable k-ε was adopted to study the flow field of SUV of flat underground. Then the SUV of complex underground was simulated with the same mesh strategy and boundary condition. The aerodynamic drag coefficient of latter was bigger than former. That illuminated the complex underground has affect to aerodynamic performance of vehicle. The wind tunnel test validated the veracity of numerical simulation. Based on that, the underground cover board was appended; the aerodynamic drag coefficient was depressed. The velocity and pressure distribution and flow line were achieved. The conclusions provide theoretical reference for the further study of aerodynamic drag reduction of complex underground.

scholarly journals Bionic shape design of electric locomotive and aerodynamic drag reduction

2018 ◽  
Vol 4 (48) ◽  
pp. 99-109
Author(s):  
Zhenfeng WU ◽  
Yanzhong HUO ◽  
Wangcai DING ◽  
Zihao XIE
Keyword(s):  
Flow Field ◽  
Drag Reduction ◽  
Bluff Body ◽  
Aerodynamic Drag ◽  
Geometric Characteristic ◽  
Shape Design ◽  
Shape Optimisation ◽  
Electric Locomotive ◽  
Geometric Models ◽  
Characteristic Lines

Bionics has been widely used in many fields. Previous studies on the application of bionics in locomotives and vehicles mainly focused on shape optimisation of high-speed trains, but the research on bionic shape design in the electric locomotive field is rare. This study investigated a design method for streamlined electric locomotives according to the principles of bionics. The crocodiles were chosen as the bionic object because of their powerful and streamlined head shape. Firstly, geometric characteristic lines were extracted from the head of a crocodile by analysing the head features. Secondly, according to the actual size requirements of the electric locomotive head, a free-hand sketch of the bionic electric locomotive head was completed by adjusting the position and scale of the geometric characteristic lines. Finally, the non-uniform rational B-splines method was used to establish a 3D digital model of the crocodile bionic electric locomotive, and the main and auxiliary control lines were created. To verify the drag reduction effect of the crocodile bionic electric locomotive, numerical simulations of aerodynamic drag were performed for the crocodile bionic and bluff body electric locomotives at different speeds in open air by using the CFD software, ANSYS FLUENT16.0. The geometric models of crocodile bionic and bluff body electric locomotives were both marshalled with three cars, namely, locomotive + middle car + locomotive, and the size of the two geometric models was uniform. Dimensions and grids of the flow field were defined. And then, according to the principle of motion relativity, boundary conditions of flow field were defined. The results indicated that the crocodile bionic electric locomotive demonstrated a good aerodynamic performance. At the six sampling speeds in the range of 40–240 km/h, the aerodynamic drag coefficient of the crocodile bionic electric locomotive decreased by 7.7% on the average compared with that of the bluff body electric locomotive.

scholarly journals Tandem-wing interactions on aerodynamic performance inspired by dragonfly hovering

2021 ◽  
Vol 8 (8) ◽  
pp. 202275
Author(s):  
Liansong Peng ◽  
Mengzong Zheng ◽  
Tianyu Pan ◽  
Guanting Su ◽  
Qiushi Li
Keyword(s):  
Body Weight ◽  
Flow Field ◽  
Numerical Simulations ◽  
Phase Difference ◽  
High Efficiency ◽  
Lift Coefficient ◽  
Aerodynamic Performance ◽  
The Body ◽  
Wing Surface ◽  
Phase Differences

Dragonflies possess two pairs of wings and the interactions between forewing (FW) and hindwing (HW) play an important role in dragonfly flight. The effects of tandem-wing (TW) interactions on the aerodynamic performance of dragonfly hovering have been investigated. Numerical simulations of single-wing hovering without interactions and TW hovering with interactions are conducted and compared. It is found that the TW interactions reduce the lift coefficient of FW and HW by 7.36% and 20.25% and also decrease the aerodynamic power and efficiency. The above effects are mainly caused by the interaction between the vortex structures of the FW and the HW, which makes the pressure of the wing surface and the flow field near the wings change. During the observations of dragonfly flight, it is found that the phase difference ( γ ) is not fixed. To explore the influence of phase difference on aerodynamic performance, TW hovering with different phase differences is studied. The results show that at γ = 22.5°, dragonflies produce the maximum lift which is more than 20% of the body weight with high efficiency; at γ = 180°, dragonflies generate the same lift as the body weight.

Study of Truck’s Aerodynamic Drag Reduction Based on Jet

2014 ◽  
Vol 635-637 ◽  
pp. 316-319
Author(s):  
Peng Guo ◽  
Jun Yuan Zhang ◽  
Qi Fei Li ◽  
Xing Jun Hu
Keyword(s):  
Numerical Simulation ◽  
Comparative Analysis ◽  
Flow Field ◽  
Drag Reduction ◽  
Pressure Distribution ◽  
Aerodynamic Drag ◽  
Outer Flow ◽  
Air Movement ◽  
Maximum Drag Reduction ◽  
Aerodynamic Drag Reduction

Multiple schemes are adapted on truck's outer flow field based on numerical simulation. Comparative analysis with the state of air flow, the pressure distribution, the air movement between the cab and cargo is pursued, then obtain the effect of jet flow velocity to the truck Cd. With the increasing of the jet velocity, Cd increases first and then decreases. The maximum drag reduction can reaches 7.38%.

Numerical simulation of the flow field over conical, disc and flat spiked body at Mach 6

2010 ◽  
Vol 114 (1154) ◽  
pp. 225-236 ◽  
Author(s):  
R. C. Mehta
Keyword(s):  
Flow Field ◽  
Drag Reduction ◽  
High Speed ◽  
Blunt Body ◽  
Stokes Equations ◽  
Aerodynamic Drag ◽  
Dynamic Pressure ◽  
Recirculation Region ◽  
Potential Candidate ◽  
Wave Separation

Abstract A forward facing spike attached to a hemispherical body significantly changes its flow field and influences aerodynamic drag and wall heat flux in a high speed flow. The dynamic pressure in the recirculation area is highly reduced and this leads to the decrease in the aerodynamic drag and heat load on the surface. Consequently, the geometry, that is, the length and shape of the spike, has to be simulated in order to obtain a large conical recirculation region in front of the blunt body to get beneficial drag reduction. It is, therefore, a potential candidate for aerodynamic drag reduction for a future high speed vehicle. Axisymmetric compressible laminar Navier-Stokes equations are solved using a finite volume discretisation in conjunction with a multistage Runge-Kutta time stepping scheme. The effect of the spike length and shape, and the spike nose configuration on the reduction of drag is numerically evaluated at Mach 6 at a zero angle-of-attack. The computed density contours agree well with the schlieren images. Additional modification to the tip of the spike to get different types of flow field such as the formation of a shock wave, separation area and reattachment point are examined. The spike geometries include the conical spike, the flat-disk spike and the hemispherical disk spike of different length to diameter ratios attached to the blunt body.

Numerical Simulation of Influence of Different Deflectors on Aerodynamic Characteristics of the Heavy Duty Truck

2013 ◽  
Vol 365-366 ◽  
pp. 474-477
Author(s):  
Yu Kun Liu ◽  
Qi Fei Li ◽  
Guan Qun Li ◽  
Ao Liu ◽  
Xing Jun Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Drag Reduction ◽  
Aerodynamic Drag ◽  
Optimal Solution ◽  
Aerodynamic Characteristics ◽  
Heavy Duty ◽  
Heavy Duty Truck

In order to reduce the aerodynamic drag of heavy-duty truck, four different shape and style of deflectors based on the original one are added. With the method of numerical simulation, the influence of deflector on the flow field of the cab and the vehicle was analyzed, and the mechanism of aerodynamic drag and the measures of drag reduction were discussed in the study. When driving at speed of 30m/s, the aerodynamic drag will be significantly reduced with the contributions of all the four deflectors. The optimal solution can reach a reduction about 14%.

Numerical Analyses to Investigate the Impact of External Sun Visor on Aerodynamic Drag of Heavy-Duty Commercial Truck

2014 ◽  
Vol 602-605 ◽  
pp. 787-790
Author(s):  
Han Bo Yang ◽  
Xing Jun Hu ◽  
Teng Fei Li
Keyword(s):  
Flow Field ◽  
Drag Reduction ◽  
Aerodynamic Drag ◽  
Great Influence ◽  
Heavy Duty ◽  
Local Flow ◽  
Heavy Duty Truck ◽  
Aerodynamic Drag Reduction ◽  
The Impact

Aerodynamic drag is one of the most important sources of the driving resistance suffered by an on-road heavy-duty truck. The previous studies have rarely involved the role of the external sun visor. Therefore, numerical method is used for the research of the influence of six kinds of sun visors differenced by shapes or layouts on the aerodynamic drag reduction. It is demonstrated that the sun visor has a great influence on the local flow field where it is fixed, while a relatively small effect on the global flow field. Moreover, compared to the original one, the CDvalues of each case have different degrees of reduction which illustrates that an appropriate shape and layout of a sun visor benefits the air drag reduction, the largest decline is 4.7%.

Aerodynamic behavior of a high-speed train with a braking plate mounted in the region of inter-car gap or uniform-car body: A comparative numerical study

2020 ◽  
pp. 095440972096582
Author(s):  
Jiqiang Niu ◽  
Yueming Wang ◽  
Feng Liu ◽  
Rui Li
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Body Region ◽  
High Speed Train ◽  
Detached Eddy Simulation ◽  
Continuous Increase ◽  
Car Body

The continuous increase in train speed has brought serious challenges to train braking safety. Aerodynamic braking technology can effectively improve the braking effect of trains at high speeds. In this study, an aerodynamic braking device installed in the inter-car gap region (ICG) of a high-speed train is proposed and the aerodynamic performance of the high-speed train with an aerodynamic braking device is assessed by improved delayed detached eddy simulation (IDDES) based on the κ-ω turbulence model. The results show that the opening of the plate significantly changes the aerodynamic performance of the train, thereby greatly increasing the aerodynamic forces of the train and their fluctuation degree. The effect of the opening of the plate increases the turbulence of the downstream flow field around the tail car. The affected area is mainly concentrated in the flow field around the location of the plate for the pressure field and the whole flow field behind the plate for the velocity field. The effect of the plate mounted on the uniform-car body region (UCG) on increasing the aerodynamic drag is better than that at the ICG, though the aerodynamic fluctuation and the influence on the surrounding flow field will also be great.

A Study of an Active Rear Diffuser Device for Aerodynamic Drag Reduction of Automobiles

2012 ◽  
Author(s):  
Seung-On Kang ◽  
Jun-Ho Cho ◽  
Sang-Ook Jun ◽  
Hoon-Il Park ◽  
Ki-Sun Song ◽  
...  
Keyword(s):  
Drag Reduction ◽  
Aerodynamic Drag ◽  
Aerodynamic Drag Reduction
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